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. 2009 Jul 29;4(7):e6426. doi: 10.1371/journal.pone.0006426

Table 4. Analysis of diagnostic factors at presentation for N.meningitidis, S.pneumoniae, H.influenzae, and Others.

Diagnostic Factors N.meningitidis S. pneumoniae H. influenzae Other
RR 95%CI P PPV 95%CI RR 95%CI P PPV 95%CI RR 95%CI P PPV 95%CI RR 95%CI P PPV 95%CI
CSF Fluid Analysis at Presentation
Positive CSF culture 0.72 0.67–0.78 <0.001 58.3 55.1–61.4 1.98 1.25–3.12 0.002 15.2 13.0–17.7 2.63 1.72–4.03 <0.001 22.4 19.2–25.1 1.28 0.61–2.70 0.516 4.1 3.0–5.6
Positive Gram stain 0.78 0.71–0.85 <0.001 57.5 54.0–61.0 2.61 1.74–3.92 <0.001 17.9 15.3–20.8 1.64 1.23–2.20 0.001 22.1 19.2–25.2 0.44 0.24–0.81 0.006 2.6 1.6–4.0
CSF WBC≤100/µL 1.47 1.36–1.58 <0.001 85.9 80.2–90.4 0.54 0.33–0.88 0.005 8.1 4.7–12.8 0.07 0.02–0.21 <0.001 1.5 0.3–4.4 1.12 0.56–2.25 0.756 4.5 2.1–8.5
CSF WBC≤1000/µL 1.20 1.10–1.30 <0.001 70.4 65.8–74.6 1.17 0.89–1.55 0.271 15.4 12.2–19.2 0.34 0.25–0.48 <0.001 8.5 6.1–11.6 1.72 1.02–2.89 0.041 5.7 3.8–8.5
CSF Glu<40 mg/dL 0.71 0.66–0.78 <0.001 53.6 49.8–57.3 1.19 0.89–1.59 0.238 14.4 12.0–17.3 2.80 2.11–3.72 <0.001 27.3 24.1–30.8 1.48 0.83–2.63 0.179 4.6 3.3–6.5
CSF Protein>100 mg/dL 0.81 0.75–0.88 <0.001 57.0 53.2–60.7 1.35 1.01–1.81 0.044 15.2 12.6–18.1 1.53 1.20–1.94 <0.001 23.2 20.2–26.6 1.42 0.80–2.49 0.226 4.6 3.2–6.5
≥65% neutrophils in CSF 1.02 0.8–1.21 0.774 60.1 56.9–63.2 0.89 0.55–1.43 0.624 13.6 11.6–16.0 1.22 0.80–1.87 0.338 22.4 19.8–25.1 0.51 0.24–1.06 0.067 3.9 2.8–5.4
Peripheral Blood Analysis at Presentation
Positive blood culture 0.85 0.75–0.95 0.004 55.9 49.9–61.8 1.30 0.94–1.81 0.117 16.8 12.6–21.8 1.10 0.83–1.47 0.499 20.1 15.5–25.3 2.45 1.33–4.52 0.003 7.2 4.4–10.9
Peripheral WBC<5000/µL 0.84 0.69–1.02 0.052 53.9 43.0–64.6 0.73 0.39–1.37 0.315 10.1 4.7–18.3 1.41 0.97–2.05 0.079 25.8 17.1–36.2 2.81 1.41–5.58 0.008 10.1 4.7–18.3
Peripheral WBC>15000/µL 1.07 0.99–1.17 0.095 66.0 61.9–69.9 1.55 1.17–2.04 0.002 17.0 14.0–20.5 0.66 0.56–0.85 0.001 14.7 11.9–17.9 0.43 0.23–0.79 0.005 2.3 1.3–4.0
Absolute blood neutrophil count<1000/µL 0.94 0.62–1.43 0.771 60.0 32.3–83.7 0.49 0.07–3.30 0.708 6.7 0.2–31.9 0.70 0.19–2.57 0.750 13.3 1.7–40.5 5.13 1.79–14.68 0.021 20.0 4.3–48.1